Food and Agriculture

1. Food and Agriculture

2. Outline • Food and Nutrition • Key Food Sources • Soil • Structure • Erosion • Agricultural Resources • Water • Energy • Genetic Engineering • Sustainable Agriculture

3. FOOD AND NUTRITION • World food supplies have more than kept up with human population growth over the past two centuries. • During the past 40 years, population growth has averaged 1.7% per year, while food production increased an average 2.2%. • Food is not necessarily grown or distributed equitably.

4. Chronic Hunger and Food Security • Poverty is the greatest threat to food security (= Ability to obtain sufficient food on a daily basis). • Operates on multiple levels. • Recognizing the role of women in food production is an important step forward.

5. Risk of Inadequate Nutrition

6. Acute Food Shortages • Famines are characterized by large-scale food shortages, massive starvation, social disruption, and economic chaos. • Mass migrations often occur because productive capacity has been sacrificed. • Environmental conditions are immediate trigger, but politics and economics are often the underlying problems. • Arbitrary political boundaries block historic access to refuge areas.

7. Famines • Aid policies of economically wealthy countries often serve to distribute surplus commodities and produce feeling of generosity. But: • Food camps have serious drawbacks: • Stress and crowding • Lack of sanitation • Close contact to epidemic diseases • “Teach a person to fish…”

8. Malnutrition and Obesity • Malnourishment - Nutritional imbalance caused by a lack of specific dietary components. • In poorer countries, people often cannot afford to purchase an adequate variety of nutritious foods.

9. Obesity • The most common dietary problem in wealthy countries is over-nutrition. • According to U.S. Surgeon General: • 62% of Americans are overweight. • 33% are obese. • http://www.cdc.gov/ obesity/data/trends.html • http://www.nhlbisupport.com/bmi

10. Nutritional Problems • Iron deficiency is the most common dietary imbalance in the world. • Leads to anemia. • Increases risk of death from hemorrhage in childbirth and affects development. • Red meat, eggs, legumes, and green vegetables are all good sources of iron.

11. Protein Deficiency Diseases • Kwashiorkor - “Displaced Child” - Occurs mainly in children whose diet lacks high-quality protein. • Reddish-orange hair, bloated stomach. • Marasmus - “To Waste Away” - Caused by a diet low in protein and calories. • Very thin, shriveled.

12. KEY FOOD SOURCES • Three crops deliver majority of world’s nutrients: • Wheat, Rice, and Corn • Potatoes, barley, oats, and rye are staples in cool, moist climates. • Cassava, sweet potatoes, and other roots and tubers are staples in warm, wet climates.

13. Meat and Dairy • Distribution highly inequitable. • More-developed countries make up 20% of world population, but consume 80% of meat and dairy production. • 60% of production occurs in less-developed countries. • 90% of grain grown in North America (NA) is used to feed livestock. • FAO claims using cereals as animal feed does not contribute to hunger and undernutrition. (?!)

14. Seafood • Seafood is an important protein source. • Since 1989, 13/17 major fisheries have declined or become commercially unsustainable. • FAO estimates operating costs for the 4 million boats now harvesting wild fish exceed fish sales by $50 billion annually. • Aquaculture is providing an increasing share of the world’s seafood. (Environmental costs?)

15. FARM POLICY • Farm subsidies in many countries -- including ours -- are protected by powerful political and economic interests. • Agricultural subsidies encourage surpluses and allow American farmers to sell products overseas at prices below their production costs.

16. SOIL: A RENEWABLE RESOURCE • Soil - A complex mixture of weathered minerals, partially decomposed organic materials, and a host of living organisms. • At least 15,000 different soil types in the USA. • Vary due to influences of parent material, time, topography, climate, and organisms. • Can be replenished and renewed. • Can be depleted and degraded.

17. Soil Composition • Particle size affects soil characteristics. • Spaces between sand particles give sandy soil good drainage and allow aeration. • But can easily dry out. • Tight packing of small particles in silty or clayey soils makes them less permeable to air and water.

18. Soil Composition • Soil exhibits wide range of organic content. • Humus - Insoluble residue from partially decomposed plants and animals. • Most significant factor in soil structure. • Activity of organisms living in soil helps create structure, fertility, and cultivation suitability.

19. Soil Organisms • Activity of organisms living in the soil helps create structure, fertility, and tilth (proper structure & nutrients to grow healthy crops). • Mycorrhizal symbiosis between plants roots and specific fungal species.

20. Soil Profiles • Soils are stratified into horizontal layers called soil horizons. • Together make up soil profile. • O Horizon (Organic layer) • Leaf litter, partially decomposed organisms. • A Horizon (Topsoil) • Mineral particles mixed with organic material.

21. Soil Profiles • E Horizon (Leached) • Depleted of soluble nutrients. • B Horizon (Subsoil) • Often dense texture from accumulating nutrients. • C Horizon (Parent Material) • Weathered rock fragments with little organic material.

23. Soil Types • Soils are classified according to structure and composition (12 Orders): • Mollisols Andisols • Alfisols Vertisols • Spodosols Histosols • Oxisols Inceptisols • Ultisols Entisols • Aridosols Gelisols

24. WAYS WE USE AND ABUSE SOILS • Approximately 11% of Earth’s land area is currently in agricultural production. • Up to 4 times as much could potentially be converted to agricultural use. • Much of this additional land suffers from constraints.

25. Land Resources • In developed countries, 95% of recent agricultural growth has been from altered agricultural practices (pesticides, fertilizer). • Less land cultivated in NA now than 100 years ago. • Many developing countries are reaching limit of lands that can be exploited for agriculture without unacceptable social and environmental costs.

26. Land Degradation • Every year, about: • 3 million hectares (ha) of cropland are ruined annually via erosion • 4 million ha are transformed into deserts • 8 million ha are converted to non-agricultural uses • 1 hectare = 10,000 m2 = ~2.5 acres

27. Land Degradation • Definitions of degradation are based on both biological productivity and expectations of what land should be like. • Generally, land is considered degraded when soil is impoverished or eroded, run-off is contaminated, or biodiversity is diminished. • Water and wind are the driving forces for vast majority of soil degradation.

28. Global Soil Degradation

29. Erosion • Erosion is an important natural process, resulting in redistribution of the products of geologic weathering, and is part of both soil formation and soil loss. • Tends to begin subtly. • Worldwide, erosion reduces crop production by equivalent of 1% of world cropland per year.

30. Mechanisms of Erosion • Sheet Erosion - Thin layer of surface removed. • Rill Erosion - Small rivulets of running water gather together and cut small channels. • Gully Erosion - Rills enlarge to form bigger channels too large to be removed by normal tillage. • Streambank Erosion - Washing away of soil from established streambanks.

31. Mechanisms of Erosion • Wind can equal or exceed water as an erosive force, especially in a dry climate and on flat land. • Intensive farming practices: • Row crops leave soil exposed. • Weed free fields. • Removal of windbreaks. • No crop-rotation or resting periods. • Continued monocultures.

32. OTHER AGRICULTURAL RESOURCES • Water • Agriculture accounts for largest single share of global water use. • As much as 80% of the water withdrawn for irrigation never reaches its intended destination. • Cheap cost encourages over-use. • Waterlogging • Salinization

33. Fertilizer • Lack of nitrogen (N), potassium (K), and phosphorus (P) often limits plant growth. • Adding nutrients via fertilizer usually stimulates growth and increases crop yields. • 1950 - Average of 20 kg/ha fertilizer used. • 1990 - Average of 91 kg/ha fertilizer used. • Manure and nitrogen-fixing bacteria are alternative methods of replenishing soil nutrients.

34. Energy • Farming in industrialized countries is highly energy-intensive. • Between 1920-1980, energy use rose directly with mechanization of agriculture, and indirectly with spraying of chemicals. • Altogether, USA food system consumes 16% of total energy use. • Most foods require more energy to produce, process, and transport than we yield from them.

35. NEW CROPS AND GENETIC ENGINEERING • Most of world food comes from 16 widely grown crops. • At least 3,000 species of plants have been used for food at some point in time. • Many new or unconventional varieties might be valuable food supplies.

36. Genetic Engineering • Genetically Modified Organisms (GMO’s) • Contain DNA possessing genes borrowed from unrelated species. • May produce crops with pest-resistance and wider tolerance levels. • But, traits might spread to wild varieties, and increased expense would largely hurt smaller farmers. • Estimated that 60% of all processed foods in NA contain transgenic products.

37. Pest Resistance and Weed Control • Biotechnologists have recently created plants containing genes for endogenous insecticides. • Concern has arisen over several points. • Spread of genes into wild populations leading to resistance in pests. • Effect on nontarget species.

38. Is Genetic Engineering Safe? • Environmental and consumer groups have campaigned against transgenic organisms. • “Frankenfoods” • USA Food and Drug Administration (FDA) declined to require labeling of foods containing GMOs. • New varieties are “substantially equivalent” to related traditionally bred varieties. (Do we really know yet? Are consumers the “guinea pigs”?)

39. SUSTAINABLE AGRICULTURE • Soil Conservation • Managing Topography • Contour Plowing - Plowing across slope to slow flow of water. • Strip Farming - Planting different crops in alternating strips along land contours. • Terracing - Shaping land to create level shelves of earth to hold water and soil. • Plant perennial species.

40. Sustainable Agriculture

41. Soil Conservation • Providing Ground Cover • Annual row crops cause highest rates of erosion because they leave soil bare for much of the year. • Leave crop residue after harvest. • Plant cover crops after harvest.

42. Soil Conservation • Reduced Tillage • Minimum Till - Chisel plow • Conserv-Till -Coulter (Disc) • No-Till - Drilling • Often farmers using conservation tillage must depend relatively heavily on pesticides. • Traditional tillage helped control weeds and pests.

43. Low-Input Sustainable Agriculture • Do not depend on chemical fertilizers and pesticides, and use antibiotics only to combat illness. • Production costs are lower, and often obtain higher prices.